The micromechanics of self-affine fractal cracks in brittle materials

Micro-structural effects on the fractality of cracks in brittle and quasi-brittle materials will be investigated. Irregularities of fracture surface described by self-similar or self-affine fractals will be followed in the direct relationship tomicro-mechanisms of fracture initiation and propagation and as a function of local energy release rate and crack velocity. Since the fracture surfaces correspond to conditions of self-affinity in almost all cases, new transformation of such surfaceco-ordinates will be found so that surface roughness image is scale invariant. The principal aim of the project is to formulate a fractal model for prediction of fracture damage development from its initiation to final brittle fracture instability. Themodel will be experimentally verified on selected ceramics, steels and other quasi-brittle materials. Fractal modelling of fracture surface creation in brittle materials could reveal new geometrical sources of toughening. Using an experimental data and